This is an application for a K01 Career Development Award under the mentorship of Dr. Jacob Friedman at the University of Colorado Anschutz - Medical Campus. The parent project for this K01 award is a Bill and Melinda Gates Foundation-sponsored randomized control trial called Women First (clinicaltrials.gov NCT01883193). Women first is a large mother-infant longitudinal birth cohort in the 3rd world (4 international sites) that is investigating whether timing of nutritional intervention can improve maternal and infant outcomes. This K01 award will examine one international site (Guatemala) that is prone to both growth stunting and obesity. My proposed research project will assess changes in DNA methylation in umbilical cord blood (UCB) from infants born to lean or obese mothers who consumed micronutrient supplementation (MNS) for ? 3 months prior to conception (Arm 1), MNS commenced at 12 wk gestation (Arm 2), or no supplementation (Arm 3) and offspring susceptibility for stunted growth (birth length) and obesity (weight-for-length Z-score). My primary hypothesis is that maternal nutritional and metabolic status, prior to conception, will result in differentially methylation regions (DMRs) in umbilical cord blood (UCB) associated with linear growth and susceptibility to obesity. Specifically, I propose 3 novel approaches to examine the effects of pre-conception MNS and pre-pregnancy BMI on the infant epigenome: SA1) Identification of differentially methylated regions using Roche - NimbleGen SeqCap Epi SA2) Assessing DNA methylation of newly identified obesity-associated metastable epialleles SA3) Use 2-step Mendelian Randomization to strengthen causal inference of my postulated pathway: Maternal MNS & pre-pregnancy BMI ? ? DNA methylation ? infant outcome (birth length & body weight) Due to limited experience assessing epigenetics in large clinical cohorts, I have devised a specific training plan to acquire epigenetic, clinical, and analytical skills. I hve identified mentors at Anschutz Medical Campus who are highly productive leaders in developmental programming and obesity (Dr. Jed Friedman), international nutrition and pediatrics (Dr. Nancy Krebs), epigenetics (Dr. Ivana Yang), bioinformatics (Dr. Kenneth Jones), and epidemiology (Dr. Dana Dabalea). My training plan will also take advantage of 2 key international experts i) Dr. Caroline Relton, who has pioneered 2-step Mendelian randomization, and ii) Dr. John Greally, who has helped innovate the SeqCap Epi methodology with Roche-NimbleGen as well as numerous other epigenetic-related accolades. My training plan encompasses cutting edge epigenetic analysis tools, an outstanding network of advisors, and an innovative tool-kit to facilitate a successful transition to an independent career in translatioal epigenetics and the developmental origins of obesity.